To partially plate a member to be plated, methods are widely used in which plating is applied while masking a region not to be plated of a member to be plated using a material such as a masking tape, a rubber insulator, and a polymer resist, and in which plating is applied by injecting a plating solution onto a region to be plated while energizing the member to be plated.
However, it is difficult to plate a minute region of a member to be plated by the above methods because the partial plating method using masking requires masking on a member to be plated, and the partial plating method using injection involves a large injection diameter.
As for a plating method capable of plating a minute region of a member to be plated, a plating method using a laser beam is known.
For example, Japanese Patent Examined Publication No. S59-1797 discloses a method for electroplating which projects a laser beam having intensity in a specific range onto a selected region to be metal plated and heats the region. By projecting the laser beam onto the selected region to be metal plated, the selected region is locally heated and the plating rate thereof is increased, thereby allowing partial plating on the selected region. Such a laser plating method focuses the laser beam onto a minute region in order to locally project the laser beam, and thus it is possible to plate the minute region of the member to be plated.
As the laser beam source, an argon ion laser beam source is mainly used. The argon ion laser, having a wavelength of about 500 nm which is absorbed by metal, is suitable for locally heating a metal member to be plated and capable of yielding high output.
In addition, connecting portions with other components or terminal portions of electric/electronic components such as connectors, switches, and lead materials are conventionally plated with metal such as tin and precious metal in order to improve characteristics such as electric connection reliability and corrosion resistance.
In particular, precious metals such as gold, palladium, silver and alloys thereof may be plated onto a region in which high connection reliability is required. In such a case, plating on regions other than regions which need to be plated results in an increased cost for manufacturing the components, due to high prices of precious metals. Accordingly, partial plating which selectively plates regions which need to be plated is used for such components.
With recent downsizing of electric/electronic devices, connecting components used for electric/electronic devices and electric/electronic components have become smaller, and accordingly regions to be plated of these components have become minute, which requires high positional precision in plating.
For example, when manufacturing a connector female terminal having an electric contact portion inside, hard gold plating is partially applied to a minute region of a ribbon plate, and then a coupled body in which a number of terminals are coupled to a carrier frame is formed by press working. To minimize the plating region, high positional precision of the plating region is required in order to avoid positional difference with the press working to be performed after the plating.
A plating device which can apply partial plating to a minute region of a member to be plated with high positional precision is disclosed in Japanese Patent No. 2645201. Japanese Patent No. 2645201 discloses a plating device which comprises a wheel-shaped guide means along which a member to be plated can be passed, and an endless masking means which is provided with a passage whose shape is adapted to a desired dot-shaped plating of the member to be plated.
The endless masking means comprises independent masking segments which are coupled in a manner which permits movement of the masking segments with respect to each other in a longitudinal direction, and each masking segment comprises a pilot pin. The pilot pin engages a positioning recess provided in the member to be plated, such that each masking segment is fully adjustable with respect to the plating region of the member to be plated. Accordingly, partial plating can be applied with high positional precision to a minute region of the member to be plated.